The invention relates to antivibration mounts and methods for manufacturing these mounts. More particularly, the invention relates to an antivibration mount for interposing between two rigid elements to damp vibration therebetween, essentially in a main vibration direction, the mount comprising:
first and second rigid strength members suitable for securing to respective ones of the two rigid elements to be united,
an elastomer body interconnecting the two rigid strength members,
and limitation means for limiting movements of the first and second strength members away from each other.
Such a mount is described, for example, in document U.S. Pat. No. 5,330,163 in which the limitation means are constituted by a flexible ring which is passed around the first and second strength members.
In other known examples of antivibration mounts, the limitation means may be constituted by a rigid member such as a stem with enlarged foot, which is fixed to the first strength member and passes through the elastomer body and the second strength member with slack.
In all cases, the limitation means require at least an additional piece, which renders the mount more expensive and more difficult to manufacture.
A particular object of the present invention is to remedy these drawbacks by providing an antivibration mount of the kind in question which is simpler, cheaper and easier to manufacture than the known antivibration mounts.
To this end, according to the invention, the first strength member includes two fingers which are substantially perpendicular to the main vibration direction and which extend outwards in opposite directions, and the second rigid strength member includes first and second folded tabs which are substantially perpendicular to said fingers and pierced by windows, said two fingers of the first rigid strength member passing through said windows respectively to constitute thereby said limitation means.
In preferred embodiments of the invention, one may possibly have recourse in addition to one and/or other of the following arrangements:
the second rigid strength member is a metal plate which is substantially U-shaped, with a basis and two integral lateral wings which constitute the tabs;
the fingers are integral with the first strength member;
elastomeric stops are secured to one element chosen from the group consisting in said first rigid strength member and said second rigid strength member, said stops cooperating with counter-abutment means for limiting relative movements of the first and second strength members away from each other;
said stops are molded on the tabs of the second strength member and are oriented towards the first strength member so as to cooperate therewith;
the second rigid strength member comprises at least one folded tongue and a single threaded pin, said tongue and said pin extending in a direction opposite to the direction of the first rigid strength member.
Another object of the present invention is a mechanical assembly comprising:
a vehicle motor;
a vehicle chassis;
an antivibration mount to damp vibration between said motor and said chassis, essentially in a main vibration direction comprising first and second rigid strength members suitable for securing respectively to the vehicle motor and the vehicle chassis, an elastomer body interconnecting the two rigid strength members, and limitation means for limiting movements of the first and second strength members away from each other, wherein the first strength member includes first and second fingers which are substantially perpendicular to the main vibration direction and which extend outwards in opposite directions, and wherein the second rigid strength member includes first and second folded tabs which are substantially perpendicular to said fingers and pierced by windows, said two fingers of the first rigid strength member passing through said windows respectively to constitute thereby said limitation means;
a motor bracket interconnecting the first strength member of the antivibration mount and the vehicle motor;
wherein the first strength member includes a planar basis which extends in an oblique direction and which is interposed between the motor bracket and the elastomer body, said planar basis being extended by two parallel integral lugs which extend along the main vibration direction on each side of said basis and which are fixed to the motor bracket, and wherein the second strength element includes a planar basis which is fastened in contact with the vehicle chassis and which is substantially parallel to said first strength member.
The present invention also provides a method of manufacturing an antivibration mount as defined above, said method including the steps of:
a) molding the elastomer body between the first strength member and a rigid plate which is substantially planar in shape and which includes two free ends pierced by windows;
b) folding said free ends of the plate towards the first rigid strength member for engaging respectively said windows of the free ends of the plate on said fingers of the first strength member, said plate thus forming the second strength member after folding of said free ends, and said free ends thus forming the tabs of the second strength member after folding.
Advantageously, elastomeric stops are further molded on the free ends of the plate at the step a).